Fabrication of AlGaAs/GaAs/diamond heterojunctions for diamond-collector HBTs

Sang June Cho, Dong Liu, Aaron Hardy, Jisoo Kim, Jiarui Gong, Cristian J. Herrera-Rodriguez, Edward Swinnich, Xenofon Konstantinou, Geum Yoon Oh, Doo Gun Kim, Jae Cheol Shin, John Papapolymerou, Michael Becker, Jung Hun Seo, John D. Albrecht, Timothy A. Grotjohn, Zhenqiang Ma

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Diamond is a highly attractive ultrawide bandgap semiconductor for next-generation high-power switching devices and RF devices for its superior physical and electrical properties. However, the lack of effective n-type dopants in diamond has limited the material to only unipolar p-type device applications. Heterostructure bipolar devices that use better n-type semiconductors together with p-type diamond is an approach to get high performance devices. In this work, p-n-p AlGaAs/GaAs/diamond heterojunction bipolar transistors (HBTs) are proposed and fabricated using a grafting technique. The double-heterojunction is formed by transferring an AlGaAs(p-type)/GaAs(n-type) membrane onto single-crystalline p-type doped diamond with an electron affinity of 0.32 eV. The epitaxial AlGaAs/GaAs emitter-base p-n junction shows an ideality factor of 1.09 with an Ion/Ioff of 1.53 × 107 at ± 1.5 V. The grafted GaAs/diamond n-p junction shows an ideality factor of 3.67 with an Ion/Ioff of 3.74 × 1010 at ± 5.2 V. Due to the valence-band energy barrier of 0.3 eV between the GaAs base and the diamond collector, the measured current gain for the HBT is slightly below unity. Simulations show that by reducing the electron affinity value of the p-type diamond, the base-collector energy barrier height can be correspondingly reduced, and high current gain can be expected.

Original languageEnglish
Article number125226
JournalAIP Advances
Volume10
Issue number12
DOIs
StatePublished - 1 Dec 2020

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